1. Field of the Invention
This invention relates to automotive vehicles, and more particularly concerns passenger-carrying automobiles propelled by internal combustion engines.
2. Description of the Prior Art
A conventional automobile is powered by an engine which transmits power through a transmission, thence through a differential to axles which drive a pair of wheels located on opposite lateral sides of the vehicle.
The size and power capacity of the engine is a compromise between one sufficiently large and powerful to provide adequate acceleration and climbing power, and one small enough to have acceptable fuel efficiency. Although it is known that smaller engines, which generate less power, are capable of maintaining a vehicle at a selected cruising speed and of achieving high fuel efficiency, the smaller engines have not been found practical because their low power output is insufficient to provide adequate vehicle acceleration. However, more powerful, heavier engines are more costly, and increase fuel consumption per mile travelled.
Considerable prior art exists in the area of improving the efficiency of operation of automotive vehicles. The predominant objectives of most approaches involve minimization of vehicle weight, reduction of frictional losses, matching of engine size to power requirements, and improvement of the energy transfer efficiency of the transmission and differential. In fact, many race cars, which require good fuel efficiency, are designed without a differential, and utilize either a simple, light-weight transmission, or no transmission at all. By eliminating the weight and energy transfer losses attributable to the transmission and differential, there is a considerable enhancement of fuel efficiency.
The use of multiple light-weight engines in place of a single large engine in order to achieve fuel efficiency is disclosed in U.S. Pat. No. 4,481,841. Other disclosures of wheeled vehicles employing multiple engines or motors are found in U.S. Pat. Nos. 4,306,630; 4,475,611; 5,253,724; and 5,429,543.
U.S. Pat. No. 2,462,902 to Rockwell, et. al. concerns a vehicle having paired front wheels mounted upon a rotating front axle and paired rear wheels mounted upon a rotating rear axle. A main engine drives the rear axle, and a booster engine drives the front axle. Associated with the main engine is a power train having a clutch, speed change transmission, propeller shaft, two speed rear axle drive gear, and differential. The booster engine has a power train consisting of a clutch, speed change transmission, propeller shaft, disengageable rear drive, and differential. Although the dual engines of Rockwell, et. al. provide some versatility of operation, the several requisite power train components increase the cost and weight of the vehicle.
U.S. Pat. No. 3,799,283 to Freber discloses a go-cart having two engines, each coupled by way of a centrifugal friction clutch to a rear drive axle. In such manner of construction, unless both engines are operating at the same speed to activate the clutches, one of the clutches will not be engaged, causing the output of the slower engine to be wasted.
U.S. Pat. No. 3,776,354 to Duclo, et. al. discloses an engine-torque converter unit adapted to drive the propulsion track of a snowmobile by way of an intervening jack-shaft. Although such system facilitates the delivery of controlled power to a propulsion drive means, it is not obviously applicable to a wheeled vehicle propelled by two separate engines.
None of the aforesaid disclosures however, are concerned with the dual objective of reducing the cost of the vehicle and improving fuel efficiency.
It is accordingly an object of the present invention to provide an automobile amenable to manufacture at reduced cost.
It is another object of this invention to provide an automobile as in the foregoing object which has improved efficiency of fuel consumption.
These objects and other objects and advantages of the invention will be apparent from the following description.